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Different p-states will let processor core work at different frequency level and voltage level. It's enabled by Intel Enhanced Speedstep technology.

I want to do some power management research. However, different processor's p-states capability is very different (for example, some processors will only have 2 p-states while others will have more). I know how to check it on the machine. But does anyone know if there is a place showing all the information for all Intel processors? So I can figure out which processor I am going to buy. I can not find such information on Intel's website.

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up vote 1 down vote accepted

p-state is something that cannot be controlled manually under newer version of cpu and Window, the tools used to able to manipulate it was RMClock, while the new CPU / BIOS no longer support direct controlled.

You probably should try to work with the Window Power Management utility first.
Control Panel > Power Options > Change Plan Settings > Change Advanced Power Settings > Change settings that are currently unavailable > Processor Power Management.

try to play with those settings and see if you can handle them first.

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Hi, thanks for your reply. You are right. In windows, probably it's difficult to control P-states. But in Linux, it's pretty easy. But we can only use the specific P-states burnt into the firmware during manufacture. We can not change the frequency freely. That's the reason why I want to know whether there is a way to get such information before I really get a machine(when I can easily get the P-states information) – Hao Shen May 1 '13 at 16:31
try this and see if it help, by the way, i don't think comparing the p-state when choosing processor is an good idea. reading tables in passmark should be good enough – user218473 May 1 '13 at 18:34
if your concern the energy consumption, look into this link – user218473 May 1 '13 at 18:39
Hi, I am going to do this due to my research project...:> I need to have a machine with enough P-states(two probably is not enough). Thank you though:> – Hao Shen May 1 '13 at 18:45

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